A conventional backpack is constructed of panels of lightweight, flexible material which are joined together to define a volume for receiving and holding articles to be carried on the back. Two or more of the panels may be releasably connected such as by a zipper. The panels may be separated when the zipper is open to define an opening into the interior of the backpack for removing or inserting articles. Heretofore, it has been difficult to maintain the opening for the purpose of inserting or removing articles. The flexible nature of the material making up the panels tends to cause one or both panels to collapse into the opening and close it. The difficulty is most acute when trying to insert articles into the backpack. The articles tend to engage the panel and push it into the opening.
Once the backpack is loaded, the comfort of the wearer is paramount. The load of the backpack is supported on the tops of the shoulders of the wearer. As a result straps of the backpack are generally held tightly against the top and adjacent regions of the shoulder. Many backpack materials used for the straps do not permit the wearers skin located under the straps to breathe so that the shoulder can become uncomfortably hot and induce substantial perspiration. The material forming the backpack can be sufficiently slick as to cause the strap to slip relative to the shoulder, undesirably shifting the load of the backpack. Another consequence of the load is that the tops of the shoulders experience the greatest force pressing down against them. The pressure exerted by the straps on the tops of the shoulders can itself cause discomfort, particularly on long hikes.